Continuity mistake: In the beginning, the kids are outside the school, and Mikey says, "Last?" But the sign says the fourth graders are right after the 3rd graders, right where they should be.
Continuity mistake: Near the end, Gus is standing between the two handball walls. He is looking back at TJ and Lawson, who are near the first wall. But as the camera pans out, TJ and Lawson have moved to the other handball wall.